From aa566e86c46d2264bf623e51f5840bde642548ad Mon Sep 17 00:00:00 2001 From: Mark Adler Date: Fri, 24 Aug 2012 15:02:28 -0700 Subject: [PATCH] Fix unintialized value bug in gzputc() introduced by const patches. Avoid the use of an uninitialized value when the write buffers have not been initialized. A recent change to avoid the use of strm-> next_in in order to resolve some const conflicts added the use of state->in in its place. This patch avoids the use of state->in when it is not initialized. Nothing bad would actually happen, since two variables set to the same unintialized value are subtracted. However valgrind was rightly complaining. So this fixes that. --- gzwrite.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/gzwrite.c b/gzwrite.c index bf579135..f53aace4 100644 --- a/gzwrite.c +++ b/gzwrite.c @@ -270,14 +270,16 @@ int ZEXPORT gzputc(file, c) /* try writing to input buffer for speed (state->size == 0 if buffer not initialized) */ - if (strm->avail_in == 0) - strm->next_in = state->in; - have = strm->next_in + strm->avail_in - state->in; - if (have < state->size) { - state->in[have] = c; - strm->avail_in++; - state->x.pos++; - return c & 0xff; + if (state->size) { + if (strm->avail_in == 0) + strm->next_in = state->in; + have = strm->next_in + strm->avail_in - state->in; + if (have < state->size) { + state->in[have] = c; + strm->avail_in++; + state->x.pos++; + return c & 0xff; + } } /* no room in buffer or not initialized, use gz_write() */